Automotive brake



Feb. 7, 1939. Tl FI CHASE 2,146,009

AUTOMOTIVE BRAKE Filed April 8, 1956 SMQ/Wto@ 27164022 C/zase Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE AUTOMOTIVE BRAKE Application April '8, 193s, sei-iai No. 73,273

3 Claims.

The invention relates to brakes and has been designed for use on vehicles.

An object of the invention is to provide a brake adapted to be applied tol a Wheel carried drum 5 in which brake are two shoes both arranged to be very effective for checking forward travel, one only to be highly effective for checking rearward travel.

A further object is to provide a brake wherein the above object invoives structure of high eficlency yet involving low cost.

A still further object relates to the use of hydraulic applying means comprising a plurality of similar wheel cylinders, one between each pair of adjacent ends of the shoes, the two cylinders having but a single supply conduit and a single air bleed.

Other objects and advantages will appear in the following description.

In the drawing accompanying this description:

Fig. 1 is a section through a brake drum show- Y ing the above assembly in elevation.

Fig. 2 is a section on line 2--2 of Fig. 1.

' Fig. 3 is a section on line 3-3 of Fig. 1.

Fig. 4 is a section on line 4-4 of Fig. 1.

Referring by reference characters to the drawing, numeral is used to designate the drum which is carried by the vehicle wheel. The drum is closed by a cover plate I3 secured to the axle housing at I5. Within the drum enclosure are shoes I1 and I9 movable to engage the inner surface of the drum and check its rotation. Se-

cured to the cover are anchor pins 2| and 23 lo cated dametrically opposite .each other.

An articulating link device, comprising links 21 and 21a, is pivoted to shoe I1 at 25. The ends of the links 21 and 21a are recessed to engage anchor pin 2|. A limited free rotation of the links about pivot 25 is provided as at 29. Shoe I9 40 is adapted to anchor an anchor pin 23 by links 33, 33a pivoted at 35 on shoe I9, a limited motion being provided at 31'.

Pivotally supported on anchor pin 23 is the arm 4| of a wheelcylinder 39 of va hydraulic brake system. Within cylinder 39 is a piston 43 with a. sealing cup 45. A spring 41 is located between the cup and the end of the cylinder. A screw 49 is pivoted to shoe I1 at 5|. An adjusting nut and cap 53, 55, the parts being integral or con- 50 nected together, is threaded on the screw and engages the end of the piston and is adapted also to engage the end of the cylinder when the shoe is released by springs 51, 51.

A somewhat similar cylinder 59 is located be.-

33 tween the opposite pair of shoe ends. It has an (Cl. 18S-152) arm 6| with an opening 63 surrounding, with suitable clearance, anchor pin 2|. The arm 6| is pivoted at to links 21, 21a. Within cylinder 59 is a piston 61, a seal 69, and a spring 1|. A screw 13 is pivoted at 15 to shoe I9. It is in 5 threaded engagement with an adjusting nut 11 and a cup 19 embraces the screw beneath the nut and seats on the end of the piston and cylinder under the influence of retracting spring 51. Adjustment of shoe clearance is made by rotating 10 the nuts 53 and 11, access to which is had by removing closures 8| in the cover plate I3. Adjacent cylinder 39 the backing plate I3 has an opening 83. Cylinder 39 has a projection 85 apertured as at 86 entering this opening and a fluid 15 conduit 81 from a source of uid pressure is connected to the projection by suitable fastening means 89. Apertured projection 85 is located at the lowest part of cylinder 39 as shown by Fig. 1. From the top oi.' cylinder 39 a conduit 9| connects 20 with the bottom of cylinder 59. From the top of cylinder 59 a projection 93 extends through a suitably enlarged opening in cover plate I3.

Into 93 is threaded a tapered and apertured plug 91 adapted when screwed down to close the pas- 25 sage 99 through projection 93. When the screw 91 is turned to release the seated end, passage 99 is in communication with an axial passage IIII to permit the bleeding of air from both cylinders. The passages may be kept free from foreign mat- 30 ter by a threaded member I 03. To apply the brakes, fluid pressure is applied from a suitable and conventional master cylinder (not shown) through conduits such as 81 to the cylinders 39 and 59. Since cylinder 39 is pivotally held by 35 anchor pin 23, the effect of the moving uid column is to move piston 43 and push shoe I1 against the drum, the shoe linkage 21 affording an anchorge at 2|. This action is supplemented by the eifect of the drum rotation when the vehicle 40 is traveling in a forward direction (see arrow A). These forces hold point 65 fixed from being moved to the left by the fluid pressure within cylinder 59. That fluid pressure therefore moves piston 61 and applies shoe I9 to the drum, shoe 45 I9 anchoring on pin 23. Here, again, when the drum is rotating in the direction of arrow A, the drum rotation supplements the applied pressure. Both shoes are highly eiective for checking forward travel. For checking rearward travel, the 50 tendency of the applied pressure to move piston 43 o f cylinder 39 is olset by the eiect of drum rotation on shoe I1. The cap 55 remains in contact with the cylinder which'is anchored on pin 23. This effect of drum rotation to apply shoe I1 55 is supplemented by the pressure applied in cylinder 59. The cylinder may move bodily toward the left (Fig. l) owing to the enlarged opening 63. This force is applied to the shoe I1 through the connection 65. Shoe l1 is therefore eective as a self-actuating shoe to check reverse travel. The outward movement of piston 61 in cylinder 59 is resisted by the effect of drum rotation on shoe I `Si so that shoe I9 is effective only as a non-selfactuating shoe in checking rearward travel.

I claim:

1. In a brake for vehicles, two shoes, applying means between each pair of adjacent ends of said shoes, anchor pins located between each pair of adjacent ends of said shoes, one shoe anchoring on one pin, the other shoe on the other pin under the influence of forces applied by said applying means and supplemented by the iniluence upon the shoes of that drum rotation corresponding to forward vehicle travel, the other ends of said shoes being unanchored upon said anchored pins, each said applying means comprising a'hydraulic cylinder, a piston movable therein, the cylinder of one of said applying means being anchored on one anchor pin and its piston connected to the adjacent unanchored shoe end and the cylinder and piston of the opposite applying means being connected to the adjacent shoe ends, said last-named applying means being movable relatively to the adjacent anchor pin.A l

2. In a brake, a drum, two shoes, two anchor pins, one between each pair of adjacent shoe ends, two applying means, each comprising parts having relative axial movement, one such applying means being located between each pair of adjacent shoe ends, one of said applying means having its parts connected to the adjacent shoe ends, one of said shoe ends adapted to engage a rst one of said anchor pins, the parts of the other applying means engaged with one shoe and the adjacent anchor pin, the other adjacent shoe end anchoring on the adjacent pin.

3. In a brake, a. drum, two shoes to engage the drums,an anchor between .each pair of adjacent ends, applying means between each pair of adjacent ends, one only of each pair of adjacent shoe ends engaging the adjacent anchor in response to one direction of drum rotation, each said applying means including relatively movable parts, the parts of one of said applying means being connected to the end of one shoe and to the adjacent anchor and theparts of the other applying means being connected to the two adjacent shoe ends.

'II-IERON P. CHASE. 

